As the pandemic of the Acquired Immunodeficiency Syndrome (AIDS) continues to grow, the importance of developing effective vaccines to prevent infection with Human Immunodeficiency Virus (HIV) and the development of AIDS assumes increasing importance. It is estimated that HIV is spread by sexual transmission at mucosal surfaces in 80% of cases world-wide. Until recently, candidate AIDS vaccines in Phase I trials have either not been specifically designed to induce mucosal immunity or have not been studied for their effectiveness in inducing such responses. However, new candidate AIDS vaccines, including live vector vaccines and those engineered with novel adjuvant or delivery systems for inducing a mucosal immune response, are becoming available for testing in Phase I/II Clinical Trials. Methodology for evaluating the immune responses to HIV vaccines at mucosal sites where transmission of HIV occurs. The Division of AIDS, NIAID, currently supports five AIDS Vaccine Evaluation Unit (AVEU) contracts. The AVEUs are at Johns Hopkins University, Baltimore, MD (N01-AI-05061), St. Louis University, St. Louis, MO (N01-AI-05064), University of Rochester, Rochester, NY (N01-AI- 05063), University of Washington, Seattle, WA (N01-AI-05065) and Vanderbilt University, Nashville, TN (N01-AI-05062). A Central Immunology Laboratory contract, currently held by Duke University (N01- AI-15106), serves the AVEUs providing centralized, uniform assessment of selected anti-HIV antibody and cellular immune responses of volunteers in these trials. However, these assessments do not include evaluation of the anti-HIV mucosal immune responses in the vaccinees. Therefore, this contract will establish the Mucosal Immunology Laboratory which will adapt, standardize, and perform assays for humoral and cellular mucosal immune responses induced in volunteers by immunization with prototype AIDS vaccines in Phase I/II Clinical Trials.